1. Field of the Invention
The present invention pertains to irrigation systems used for agricultural purposes, more particularly to irrigation systems that supply water to large areas, and most particularly to irrigation systems for agricultural purposes that can supply water to large areas of turf or row crops.
2. Description of the Related Art
Conventional irrigation systems include sprinklers, drip systems, flood irrigation, and french drains. In applying water to areas, the first three methods have very high water losses due to evaporation. This is not only costly, but in certain physical locations extra water may not be available for irrigation purposes. French drains can only provide water to point or line locations. Therefore, such a system cannot be used for broad areas.
Due to the problems associated with these conventional systems, specialized irrigation or watering systems have been developed for specific purposes. U.S. Pat. Nos. 4,140,421 and 4,117,685 describe underground pipe systems that require digging trenches in order to install the systems.
U.S. Pat. No. 4,001,968 describes an irrigation system for growing plants in hothouses having a sheet with one side being silica sand having a impermeable sheet with holes in it placed above the silica sand sheet placed within a pallet as used in hothouses. Water tubes are placed under the impermeable sheet and over the silica sand sheet. It is stated that the silica sand coating should not be of multiple grain thickness.
U.S. Pat. No. 4,257,191 describes using a layer of aluminum silicate above plastic foil. A pipe to distribute water is provided within the aluminum silicate layer. Above the aluminum silicate layer is a layer containing a mixture of aluminum silicate and soil. Above the mixed layer is a layer of fertile soil. The invention appears to be designed to work in planter pots or the like to grow potted plants.
U.S. Pat. No. 4,832,526 describes an underground watering system for an athletic facility having shallow, rounded trenches with a water pipe placed in the rounded bottom of the trenches. The trenches are filled with fine stone aggregate and covered with a water permeable fabric. A course layer of relatively course aggregate is placed over the fabric and another layer of relatively fine aggregate is placed over the course layer. The athletic playing surface is over the fine aggregate layer.
U.S. Pat. No. 4,878,780 describes a watertight membrane having a ballast layer of uniform rock covered by a water permeable layer. The permeable layer is covered by a layer of crushed volcanic rock or cinders. This layer, in turn, is covered by a finish layer. Water is inserted into the ballast layer. This system is dependent upon capillary action.
U.S. Pat. No. 5,006,013 describes built-up granular structure having a fine aggregate surface layer, a course aggregate reservoir layer with a topmost application of perforated adhesive material, and a dry moisture barrier layer having a topmost impervious layer. A containment wall having screened drainage surrounds the periphery of the structure to provide water.
U.S. Pat. No. 5,765,305 describes growing a transportable sod mat with grass seeds in a thin layer of growing medium spread over a mat of non-woven polypropylene laying on an impermeable membrane. After the seeds have germinated, the mat and growing medium is transplanted over a layer of porous material covering a conditioned subsoil. Drop irrigation lines are run through the upper region of the porous material.
U.S. Pat. No. 5,938,372 describes a subsurface irrigation system having a water resistant material with a pipe system placed upon it. Multiple diffusers are placed upon the pipe system having any overlaying material placed over each diffuser. Course sand may be placed over the overlaying material.
Finally, U.S. Pat. No. 6,178,691 describes a carpet irrigation system of four layers consisting of a water impermeable membrane base, a water permeable microperforated dark coloured top membrane having two water bearing capillary mats placed between the two membranes to which water are supplied through conventional irrigation.
As can be seen by the above, there have been many configurations of watering means developed for specialized purposes. However, there are inherent problems associated with all of the above systems. First, the majority of the systems must either be buried in trenches or can only be used in a pot or pallet. Therefore, if one desires to provide a simple, economical, irrigation system to a large surface area, the above systems cannot be employed or are very costly. Second, many of the above systems employ expensive or exotic materials in multiple layers such as fine stone aggregate, aluminum silicate, and specially perforated membranes. The complexity of manufacturing these systems along with the costly materials make them uneconomical for large area systems. Finally, most of these systems were designed for specialized purposes and cannot be employed for varying types of agricultural purposes. Therefore, it is desired to provide an economical system, that is easily installed, and may be used for a variety of agricultural purposes over large areas.
The present invention comprises an irrigation system that is economical and easily installed so that it may be applied to water a variety of agricultural products that cover large areas. Unlike current irrigation systems, the invention requires no trench or holes to be dug in order to accomplish installation. This greatly reduces both cost and installation time. Also, the system is made using relatively low-cost, easily obtained materials. Finally, the system contains a minimum of layers and parts so as to further reduce cost and simplify installation.
Accordingly, it is an object of this invention to provide a system to irrigate agricultural products over large areas.
It is a further object of this invention to provide a system to irrigate agricultural products over large areas that is more economical than current systems.
It is a further object of this invention to provide a system to irrigate agricultural products over large areas that can be used for a variety of different agricultural products.
A still further object of this invention is to provide a system to irrigate agricultural products over large areas that is more easily installed than current systems.
This invention accomplishes these objectives and other needs related to irrigation of agricultural products covering large areas by providing an irrigation system comprising top and bottom layers of geosynthetic material having a layer of non-cohesive, porous material between the two layers. The top geosynthetic layer comprises a permeable geosynthetic material. The bottom geosynthetic layer comprises a geosynthetic material that has a permeability equal to or less than the permeability of the top geosynthetic layer. The same geosynthetic material may be used for both layers. The non-cohesive, porous material preferably will be an easily obtained and to low-cost material such as sand, gravel, or a combination thereof. A water distribution system is placed between the geosynthetic layers with the non-cohesive, porous material in order to supply water to the non-cohesive porous material. The entire system can be placed on the specific area to be irrigated, without digging a hole or trench, and the agricultural products can be placed directly on the irrigation system, along with a layer of top soil, dependent upon the type of agricultural product.